The art has developed various forms of computerized control for industrial process machinery, such as computerized controls for injection molding machines. The injection molding process presents a useful environment for describing the present invention for at least two reasons. First, injection molding represents the preferred application of the invention. Secondly, the injection molding industry is characterized by numerous types of equipment having various parameters which can be monitored and controlled, all according to numerous recipes characteristic to individual machine users. The control system in that type of environment must be adaptable, on the one hand, to the numerous kinds of machines with which the control is apt to be used, and on the other hand, with the desires and needs of the operator in setting and adjusting the parameters according to his unique recipes.
The invention is generally applicable to control of process machines requiring relatively complex machine/operator interfaces with displays, and is especially useful in process machines and control systems which utilize multiple set points and sensed points operated according to particularized recipes relating to different applications (e.g., for forming different types of parts). In addition to injection molding, the invention will find particular applicability in the blow molding and extrusion arts. Other suitable applications will occur to the person of skill in the art upon reading of the following specification.
A relatively conventional approach to controlling a process machine such as an injection molding machine is to provide a machine controller and display/operator interface which are not only compatible with each other but which are designed to be interdependent. The operator display panel, which may or may not be in the same enclosure as the machine controller, utilizes at least some of the intelligence of the controller in performing its display function and interfacing between the machine operator and the machine itself. Thus, whenever the controller supplier intends to update or upgrade the machine controller, that task usually also involves the modification of the display to accommodate the compatibility requirements between the two.
Conceptually, it would be possible to configure a machine controller which could communicate to a self-contained unit such as a personal computer, with the operator interface accomplished primarily by interaction between the operator and the programs resident in the personal computer. It might then be possible to transfer information from the PC to the machine controller so that the machine controller can then drive the machine. That, however, is in the nature of an off-line type of approach where the PC might assist the operator in setting up recipes, but the PC is generally off-line insofar as continued running of the machine is concerned.
In the more conventional configuration, where the display panel utilizes the intelligence of the machine controller processor, problems can develop with display response time and the like because the processor, in addition to controlling the display and interfacing with the operator, must of course control the machine itself. Even in the case where a display unit includes its own processor, the processor must typically interact with the control system at the machine controller in order to perform its function, and that reduces response time, complicates the control, and gives rise to the coupled nature of the two elements of the control system which require that they be designed and modified as a unit.